The present invention relates to a structure of a back light type liquid crystal display unit in which a liquid crystal display device is composed of two transparent substrates between which liquid crystal is enclosed, wherein a light source for emitting light to transmit the device is arranged on the back face thereof and a light-emitting diode is used for the light source of the back light.
As well known, a back light type liquid crystal display unit, in which light-emitting diodes are used, is composed as follows. A liquid crystal display device is composed of two transparent substrates, which are superposed on each other, and liquid crystal is enclosed therebetween. On the back face of the device, there is provided a light guide plate, on the back face of which a light-shielding plate adheres. At least on one peripheral end surface of the light guide plate, at least one light-emitting diode chip is arranged so that beam of light emitted therefrom can be directed to the inside of the light guide plate, and light is emitted from the overall surface of the light guide plate toward the liquid crystal display device.
However, the following problems may be encountered in the related back light type liquid crystal display unit. On the back of a liquid crystal display device, there is provided a light guide plate having one or a plurality of light-emitting diode chips. Accordingly, thickness of the back light type liquid crystal display unit is increased because of the light guide plate arranged on the back face of the liquid crystal display device. Further, it is necessary to provide electrical connection members for connecting both the liquid crystal display device and the light guide plate to the outside. As a result, the size of the related back light type liquid crystal display unit is remarkably increased and further weight thereof is also increased. Furthermore, the cost is greatly raised because the number of parts is large and also the number of electrical connecting sections are large.